The placenta is a unique organ, serving multiple purposes during pregnancy. It serves as an exchange organ, ensuring an adequate flow of nutrients to the fetus, as a complex endocrine organ, transmitting signals between mother and fetus and as a barrier to the transmission of infectious agents and drugs. The (patho)physiology, biochemistry and molecular biology of placental function are not only extremely complex, but involve studies from many disciplines and a broad range of investigative techniques. It is essential that scientists and clinicians involved in research on placental function are able to meet and interact regularly to share ideas, to outline new investigative avenues and develop collaborations. The singular nature of this research field drives this unique requirement for interaction. For many years these needs have been met successfully through the annual trophoblast satellite meetings at the Society for Gynecologic Investigation and through the periodic meetings organized in the U.S. by the Rochester Trophoblast Conference. The two groups which previously organized these meetings have been reorganized as the Placenta Association of the Americas (PAA), which has as its primary objective, the continued organization of these essential meetings. This application is for funds to support those meetings. The goal of the PAA Satellite Meetings is to provide a regular, low-cost forum for topical research presentations by experts in placental biology which will encourage attendance and stimulate interest by graduate students, clinical and postdoctoral fellows. These meetings will continue as satellite meetings to the SGI from 2003 through 2007. The PAA is also planning a stand-alone meeting in September 2004 (PAA2004, Sept 25-29). The goal of this meeting is to provide a venue for in-depth discussions of a broad range of research topics in placental biology, to bring together clinical and basic scientists from a variety of fields in an atmosphere which promotes discussion and interaction, and to create a meeting in which investigators in the field of placentology, especially young investigators, can present, interact and develop new collaborative research efforts. The theme of PAA2004 is "Signaling and the Placenta" with areas of focus on 1) intergenerational signaling, 2) maternal-fetal regulatory signaling, 3) angiogenesis and oxygenation, 4) trophoblast signaling pathways, 5) signaling and toxicological interference and 6) signaling and immuno-stimulation/tolerance. In addition there will be workshops associated with the plenary sessions, oral sessions for submitted and young investigator oral presentations, poster sessions and techniques sessions. Funds are requested for the support of travel for invited speakers for both the satellite meeting and PAA2004 and for young investigator travel for PAA2004. Additional support is being sought from foundations and private corporations.